<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        //接收用户输入的年龄
        var age = prompt('请输入年龄：');
        console.log(typeof age);
        //将age从字符串转换为数字型
        //在页面输出内容
        document.write("十五年后你的年龄为："+(parseInt(age)+15));
    </script>
</body>
</html>